In public water purification plants, sodium hypochlorite which has bactericidal activity, is added to the raw water from the water source to sterilize it. Since sodium hypochlorite is unstable, substantially all of the sodium hypochlorite in the city water reaching homes or offices is already decomposed into chlorine ions. Thus, the city water supplied to the home or the office has only low bactericidal activity. City water having only low bactericidal activity cannot sterilize an outlet port of a kitchen in an office or the home, kitchen utensils such as chopping boards, etc., bath rooms, water closets, etc.
A sanitary system is used in dispensers for mixing feedstocks with water to automatically prepare soft drinks. In the sanitary system, the city water stored in a tank disposed in the dispenser is electrolyzed using chlorine generating electrodes to generate chlorine gas, generate hypochlorous acid with bactericidal activity, and sterilize the stored water (SANYO TECHNICAL REVIEW VOL. 21 NO. 1 FEB. 1989).
Japanese patent laid-open publication 4-330986 discloses a sterilizing method, wherein salt water is supplied to an electrolytic cell having a positive electrode and a negative electrode, D.C. voltage is applied across the electrodes to generate water containing free chlorine having bactericidal activity, the water containing the free chlorine is mixed with city water, and various kinds of equipment are sterilized by the mixed water.
In the above described sanitary system, water stored in the dispenser is sterilized. Thus, the above described sanitary system cannot be directly applied to sterilization of an outlet port of a kitchen in an office or in the home, kitchen utensils such as chopping boards, etc., bath rooms, water closets, etc.
In the sterilizing method disclosed in Japanese patent laid-open publication 4-330986, it is necessary to prepare salt water, supply a salt water tank with the salt water, maintain the salt water tank, etc. Thus, the sterilizing method has a disadvantage that it requires much labor for operation and maintenance of the sterilizing apparatus for carrying out the sterilizing method.